DH-132 Stock Driver/Speaker Size?

So, I found alot of useful information here while researching for a DH-132 project (Converting the headset for 3.5mm output for PC use), though I had to cut the original speakers. Ive been trying to figure out the dimensions of the original speakers so I can look into upgrading them to more modern drivers. The set I currently have is the BOSE IPCVC, so I'm unaware if there is a size difference between the VIC-1 and the VIC-3 headsets

Any ideas?

EDIT:

I guess I should include a photo:
40mm driver I salvaged from another pair of headphones next to the stock OEM driver from the DH-132 IPCVC